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Irregularly spaced tick-marks on secondary axis. [message #30478]

Wed, 01 May 2002 07:20

Paul Van Delst[1]
Messages: 1157
Registered: April 2002

Senior Member

Hey there,

I like to plot radiance data with respect to frequency (in units of centimetres^-1). However, I
would like to put a wavelength scale (in units of microns [micrometres]) on the top Xaxis. The
relationship between them is very simple but non-linear:

wavelength (um) = 10000.0 / wavenumber (cm^-1)

I have been doing this sort of thing:

FUNCTION wticks, axis, index, value
wavelength = 10000.0d / value
format = '( f5.2 )'
RETURN, STRING( wavelength, FORMAT = format )
END

PLOT, x, y, XSTYLE = 8

AXIS, XAXIS = 1, $
XRANGE = !X.CRANGE ,$
XTICKV = 10000.0d/[ 10d, 11, 12, 13, 14, 15 ], $
XTICKS = 5, $
XSTYLE = 1, $
XTICKFORMAT = 'wticks'

As you can see, the above AXIS command assumes something about the XTICKV values. However, if I
now decide to zoom into the plot such that the x-range falls between, say, 11 and 12 microns --
no wavelength scale is shown since XTICKV doesn't contain fractional wavelength values. Is
there any way to get IDL to set "nice" wavelength values (via a dynamic XTICKV for e.g.) on the
top scale based on the wavenumber range on the bottom scale?

thanx,

paulv

--
Paul van Delst Religious and cultural
CIMSS @ NOAA/NCEP/EMC purity is a fundamentalist
Ph: (301)763-8000 x7274 fantasy
Fax:(301)763-8545 V.S.Naipaul

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[Message index]

		Irregularly spaced tick-marks on secondary axis. By: Paul Van Delst[1] on Wed, 01 May 2002 07:20
		Re: Irregularly spaced tick-marks on secondary axis. By: Ken Mankoff on Thu, 02 May 2002 07:52
		Re: Irregularly spaced tick-marks on secondary axis. By: Paul Van Delst[1] on Thu, 02 May 2002 06:19
		Re: Irregularly spaced tick-marks on secondary axis. By: Ken Mankoff on Thu, 02 May 2002 05:55

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